package com.cy.java1;

/**
 *使用同步机制将单例模式中的懒汉式改写为线程安全的
 */

public class BankTest {

}

class  Bank{

    private Bank(){}

    private static Bank instance=null;

    public static Bank getInstance() {
        //方式一：效率稍差
        synchronized (Bank.class) {
            if (instance == null) {
                instance = new Bank();
            }
            return instance;
        }
    }
}
